Fluorescent lighting tubes are commonly used in a large range of lighting systems as a result of advantages such as longer life time and better luminous efficiency compared to incandescent lamps. However, in the continuous effort to reduce power consumption, it is desirable to replace conventional light tubes with still more energy efficient and environmental friendly alternatives. One such alternative is to use LED tubular light sources having a plurality of LED's arranged in a tube similar to the fluorescent tube. In order to facilitate a transition from fluorescent tube lights to LED based tubular light sources, the LED tubular light sources should be configured for allowing installation in already existing fixtures for fluorescent light tubes. However, the electrical circuitry is different in an LED based tubular light source compared to in a fluorescent light tube in that the LED based tubular light source may provide a current path between the two end caps. Hence, the internal circuitry of the tubular light source is arranged in such a way that the light source may provide an electrical connection between the connector pins at one end portion of an elongated tube and the connector pins at the opposite end portion of the elongated tube even if the light source is not active, contrary to what was possible in conventional fluorescent light tubes. In other words, it is possible that by mounting one end cap of the tubular light source in the socket of the lighting fixture, the internal circuitry will lead live voltage to the connector pins in the opposite end cap. As a result, installation of retrofitted LED tubular light sources may be a safety hazard as it is possible to first install one end cap in the mains connected fixture while having the other end cap still exposed and carrying a live potential on the connection pins of the exposed cap. Thus, there is a risk that the installer touches the exposed end cap and receives an electrical shock.
US2010/018178 discloses a suggestion on how the aforementioned safety issue may be alleviated by introducing a safety switch within the end cap of the LED tubular light source. However, a safety switch according to US2010/018178 may in some cases be unintentionally engaged when the installer is inserting the first end of the tubular light source while having already inserted the second end into the fixture, thereby still exposing the installer to potential hazard as the unconnected end cap may then have a live potential. Accordingly, there is a need for an improved safety mechanism to increase the safety for the installer when installing retrofitted LED tubular light sources.